This invention relates to lift truck vehicles for use in ultra narrow aisle applications. More particularly, this invention relates to such a vehicle having combination side frame and outrigger members. Currently, ultra narrow aisle lift trucks are finding increasing use due to the necessity of obtaining increased storage utilization from available warehouse space. For this reason very narrow aisles are being used in such warehouses. This maximizes productive storage space available in such warehouses. Ultra narrow aisle lift trucks have been developed which are very narrow and which are in fact only slightly narrower than the rather narrow aisles which they must traverse between adjacent load spaces. It is extremely desirable to be able to load and unload from both of the facing stacks on opposite sides of the narrow aisles. Further, it is necessary to be able to load at ground level as well as at higher levels typically from vertically oriented storage racks.
When loading and unloading from upper tiers, a problem is encountered since large moments are generated about the lift masts as the loads are traversed outward into the loaded spaces of the upper tiers. This requires the utilization of some sort of means for stabilizing the load. However, the narrow aisle environment leaves little room for the normal type of outrigger which is extensible from the vehicle. See U.S. Pat. No. 3,586,183 to Shaffer which is exemplary of such an outrigger. Typically, these outriggers require space to the side of the vehicle which is not readily available in the narrow aisle environments.
Further, these conventional outrigger members require additional structure which must be carried by the vehicle and effectively reduces the load carrying capability thereof.